3 research outputs found
Rh(I)-Catalyzed 1,4-Conjugate Addition of Alkenylboronic Acids to a Cyclopentenone Useful for the Synthesis of Prostaglandins
An efficient and <i>trans</i>-diastereoselective RhÂ(I)-catalyzed
1,4-conjugate addition reaction of alkenylboronic acids and a homochiral
(<i>R</i>)-4-silyloxycyclopentenone useful for the synthesis
of derivatives of prostaglandins E and F is described for the first
time. The reaction functions under mild conditions and is particularly
rapid (≤6 h) under low power (50 W) microwave irradiation at
30 °C in MeOH in the presence of a catalytic amount of KOH. Under
these conditions, 3 mol % of [RhClÂ(COD)]<sub>2</sub> is typically
required to produce high yields. The method also functions without
microwave irradiation at 3 °C in the presence of a stoichiometric
amount of KOH. Under these conditions, only 1.5 mol % of [RhClÂ(COD)]<sub>2</sub> is needed, but the reaction is considerably slower. The method
accepts a range of aryl- and alkyl-substituted alkenylboronic acids,
and its utility has been demonstrated by the synthesis of PGF<sub>2α</sub> (dinoprost) and tafluprost
Enantioselective and Rapid Rh-Catalyzed Arylation of <i>N</i>‑Tosyl- and <i>N</i>‑Nosylaldimines in Methanol
Enantiomerically
enriched tosyl-protected diarylmethylamines were
rapidly prepared by the asymmetric addition of arylboronic acids to <i>N</i>-tosylaldimines under mild conditions in the presence of
a catalyst prepared in situ from RhÂ(I) and a chiral diene ligand.
This methodology offers access to diarylmethylamines in good yields
with excellent chiral purity at room temperature using MeOH as a solvent
and NEt<sub>3</sub> as a base. Its synthetic utility was demonstrated
by the preparation of (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline
(<b>14</b>), an antagonist of the <i>N</i>-methyl-d-aspartate (NMDA) receptor
Enantioselective and Rapid Rh-Catalyzed Arylation of <i>N</i>‑Tosyl- and <i>N</i>‑Nosylaldimines in Methanol
Enantiomerically
enriched tosyl-protected diarylmethylamines were
rapidly prepared by the asymmetric addition of arylboronic acids to <i>N</i>-tosylaldimines under mild conditions in the presence of
a catalyst prepared in situ from RhÂ(I) and a chiral diene ligand.
This methodology offers access to diarylmethylamines in good yields
with excellent chiral purity at room temperature using MeOH as a solvent
and NEt<sub>3</sub> as a base. Its synthetic utility was demonstrated
by the preparation of (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline
(<b>14</b>), an antagonist of the <i>N</i>-methyl-d-aspartate (NMDA) receptor